Cooling airflow electric motor-driven pump

ABSTRACT

An improved cooling airflow electric motor-driven pump, particularly adapted for pumping condensate from refrigeration and air conditioning systems includes a reservoir body, a reservoir cover supporting an electric motor directly connect to a centrifugal pump impeller at one end of the motor rotor shaft and to an open radial blade blower wheel at the opposite end of the motor rotor shaft. The motor is mounted on the reservoir cover and a motor cover mounted on the reservoir covers defines an aerothermodynamically matched blower wheel shroud and cooling air inlet and discharge ports for the flow of cooling air across the motor and associated electronic controls.

FIELD OF THE INVENTION

The present invention relates to the field of liquid pumping, and more particularly but not by way of limitation, to an improved cooling airflow electric motor-driven condensate pump.

BACKGROUND OF THE INVENTION

A condensate pump is used especially in the field of heating and air conditioning, as well as in many other applications, where liquid condensate is generated such as when moisture or humidity is present in the ambient atmosphere. Condensate runoff from cooled surfaces, such as from coils in refrigeration or air conditioning units, must be collected and pumped to a remote location for disposal. The condensate pump typically comprises a reservoir, a float for detecting the level of condensate water in the reservoir, and a centrifugal pump driven by an electric motor controlled by the float for pumping water out of the reservoir to the remote location.

Condensate pumps are often located in extreme environments and subject to moisture, heat and contamination or fouling. Moreover, condensate pumps are frequently installed in inaccessible locations where maintenance is difficult, and therefore reliability over many years is necessary. Cost considerations have demanded economy of manufacture, and many commercial units are typically fabricated to be as inexpensive and compact as possible.

For many years, condensate pump assemblies of the general type described above have been available for the collection and disposal of condensate water. Such devices which must reliably operate largely unattended over a span of years have experienced premature failure due to excessive heating of the motor and the associated float control electronics from inadequate cooling air flow. Several prior art devices have attempted to overcome this limitation.

One such prior art device is taught by U.S. Pat. No. 6,322,326 issued to Davis et al. In '326, a plurality of vertical air outlet ventilation slots and a plurality of horizontal air inlet ventilation slots are provided in the motor cover to facilitate air ventilation. A turbine air fan, more particularly a squirrel cage, is connected to one end of the motor and effects an air flow directioned to cool the electric motor.

Another prior art device is taught by U.S. Pat. No. 7,252,482 issued to Walker et al. In '482, a plurality of horizontal slots form the cooling air discharge ports and a plurality of vertical slot, disbursed about the motor cover, form the cooling air inlet ports. A centrifugal cooling air fan, preferably of the squirrel cage type, is connected to one end of the motor for propelling cooling air through the discharge ports.

Both prior art devices utilize a squirrel cage fan and, more specifically, a forward curved multi-vane blower wheel. See 58 in '326 and 54 in '482. Impeller Fan, Squirrel Cage, Multi-vane, Runner and Disc are all used to describe fans or blowers depending what country a person is from. Typically a blower is a centrifugal device with some type of wheel and a fan is an axial device with a propeller. There are six basic types of blower wheels defined as shrouded radial blade, open radial blade, open paddle wheel, backward inclined (with flat blades or airfoil blades), forward curved multi-vane (squirrel cage), and backward curved radial.

Forward curved multi-vane blower wheels (or squirrel cages) are a mechanical device having a wheel comprised of a number of blades mounted around a hub with two end plates. They are typically used for forced cooling air at slower speeds or for moving large volumes of air at lower pressures. They require the lowest speed of any centrifugal blower wheels to move a given amount of air which limits the speed of the condensate pump since both the fan and pump are directly coupled to the motor. This means the blower wheel and pump speed are identical to the motor's rotational speed. Forward curved multi-vane blower wheels can only operate in one direction due to the fact that the blades are curved forward in the direction of rotation.

Centrifugal blowers with forward-curved blades are not aerodynamically designed to be the most efficient. Instead, they are chosen for their ability to deliver relatively high flow rates for rather restrictive packaging requirements. A centrifugal fan or blower typically draws air from the side of the fan wheel, through the wheel, turns it 90 degrees and accelerates the air due to centrifugal force as it flows over the fan blades and exits out through the discharge of the housing. For example, in '482, air enters from side face 54 a, is turned 90 degrees by fan blades 54 b and discharges out the side at periphery 54 c.

Wheels with slightly modified geometries may perform quite differently in terms of flow efficiency and noise. The objective of the blower wheel design is to provide the best wheel to meet the requirements of air flow performance, noise, structural integrity and cost. The present invention improves upon this prior art by aerothermodynamically matching the blower wheel to a blower wheel shroud disbursed about the motor cover.

OBJECTS OF THE INVENTION

It is the object of this invention to provide an electric motor-driven pump having improved cooling air flow characteristics to dissipate heat away from the motor and the electronic controls for controlling operation of the motor. It is also an objective of this invention to provide a motor cover and cooling air port locations coupled to an open radial blade blower wheel to optimize air flow across the motor to dissipate heat in the most thermally efficient manner. It is a further object of this invention to provide an improved cooling air flow electric motor-driven pump that is economical to build and easily mounted within refrigeration and air conditioning systems.

SUMMARY OF THE INVENTION

The object of the present invention are obtained by utilizing an open radial blade blower wheel in which the blades extend straight out from the hub and are perpendicular to the direction of the wheel's rotation, like a paddle wheel. Open radial blade blower wheels are generally the least efficient of the centrifugal blower wheels and a typically not used for general ventilation. However, by coupling the open radial blade blower wheel to a blower wheel shroud, the present invention achieves improved flow performance and noise characteristics.

In addition, open radial blade blower wheels are more contaminant tolerant and less sensitive to fouling due to solids build-up on the blades which would potentially plug the air inlet ports (54 a in '482) in a forward curved multi-vane blower wheel (or squirrel cage) used in the prior art. Open radial blade blower wheels can rotate in either direction which further facilitates dispersing debris from the blades. They are typically more robust then squirrel cage designs and therefore more reliable. This reliability is enhanced with the addition of the blower wheel shroud. They can operate at higher speeds because of their robustness which allows the condensate pump to operate more effectively. Open radial blade blower wheels reduce the flow induced noise generated by the blower while retaining and possibly improving the cooling air flow performance for a given speed.

Broadly speaking, the invention can be defines as an improved cooling airflow electric motor-driven pump comprising:

a reservoir body including a reservoir chamber for collecting liquid;

a reservoir cover releasably connected to and disposed over the reservoir body and including a fluid inlet port for conducting liquid to the reservoir chamber;

an open radial blade blower wheel for cooling air flow;

an electric motor mounted on the reservoir cover including a first shaft part drivingly connected to a pump impeller and a second shaft part drivingly connected to the blower wheel;

and a motor cover disposed over the motor and the blower wheel, the motor cover being releasably mounted on the reservoir cover, the motor cover including a blower wheel shroud aerothermodynamically matched to the blower wheel, an air scoop proximately located adjacent to the blower wheel shroud and disposed in a second part of the motor cover, and a means forming at least one cooling airflow flue disposed in a third part of the motor cover and formed between the air scoop second part and a fourth part of the motor cover.

The blower wheel shroud of the motor cover comprises a generally cylindrical part and is provided with a plurality of spaced apart tangential slots extending generally vertically about the blower wheel shroud periphery forming cooling air discharge ports and adjacent to the blower wheel when the motor cover is disposed on the reservoir cover to provide for cooling air discharge from a cooling air discharge chamber formed by the air scoop second part of the motor cover. The orientation of the tangential slots in the blower wheel shroud is aligned with the air flow exit angle from the blower wheel blades to enhance the aerodynamics of the cooling air flow through the cooling air discharge ports. This has the added benefit of reducing the overall noise of the unit as the disruption of airflow is minimized as it exits and enters the motor cover.

An air scoop is proximately located adjacent to the blower wheel shroud and disposed in a second part of the motor cover. The air scoop is a teardrop shaped configuration when view from the top and facilitates the air flow transition from the cooling airflow flue disposed in a third part of the motor cover to the blower wheel.

The cooling airflow flue is disposed in a third part of the motor cover. It is shaped to act as a natural draft mechanism to facilitate the air flow from the plurality of vertically extending spaced apart slots forming cooling air inlet ports disposed in the fourth part of the motor cover across the electric motor windings and the associated electronic controls for controlling operation of the motor to the air scoop.

The fourth part of the motor cover comprises a generally rectangular part and is provided with a plurality of vertically extending spaced apart slots forming cooling air inlet ports disposed in the fourth part of the motor cover and spaced from the reservoir cover.

The blower wheel shroud of the motor cover is integrally joined to the air scoop second part of the motor cover and the fourth rectangular part of the motor cover. The blower wheel shroud forms a cover for at least of a portion of the motor and the blower wheel.

The cooling air flow flue third part of the motor cover is integrally joined to the air scoop second part of the motor cover and the fourth part of the motor cover. The cooling air flow flue third part of the motor cover forms a cover for at least the float control electronics for controlling operation of the motor.

The shape of the motor cover and the location of the inlet and discharge ports coupled to an open radial blade blower wheel optimize the air flow across the motor and associated electronic controls to dissipate heat in the most thermally efficient manner.

Those skilled in the art will further appreciate the above-mentioned advantages and superior features of the pump of the present invention, together with other important aspects thereof, upon reading the detailed description which follows in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a modular condensate pump assembly constructed in accordance with the prior art as taught by U.S. Pat. No. 6,322,326;

FIG. 2 is an elevational view, in cross section, of the condensate pump assembly of FIG. 1;

FIG. 3 is a perspective view of an electric motor-driven pump constructed in accordance with the prior art as taught by U.S. Pat. No. 7,252,482;

FIG. 4 is a section view taken generally along the line 3-3 of FIG. 1;

FIG. 5 is a perspective view of an improved cooling airflow electric motor-driven pump in accordance with the present invention;

FIG. 6 is a front elevational view of the pump shown in FIG. 5;

FIG. 7 is a section view taken generally along the line 7-7 of FIG. 6; and

FIG. 8 is a plan view of the pump shown in FIG. 7 with the motor shroud or cover removed.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1 and 2 illustrate modular condensate pump assembly 10 constructed in accordance with the prior art as taught by U.S. Pat. No. 6,322,326. In FIG. 1, plurality of vertical air outlet ventilation slots 38 and plurality of horizontal air inlet ventilation slots 38A are provided in motor cover 16 to facilitate air ventilation. As shown in FIG. 2, turbine air fan 58 is a squirrel cage type connected to one end of motor 48 and effects an air flow directioned to cool electric motor 48.

FIGS. 3 and 4 illustrate electric motor-driven pump 10 in accordance with the prior art as taught by U.S. Pat. No. 7,252,482. In FIG. 3, plurality of horizontal slots 25 g form the cooling air discharge ports and plurality of vertical slot 25 a-25 f, disbursed about motor cover 24, form the cooling air inlet ports. As shown in FIG. 4, centrifugal cooling air fan 54 is preferably of a squirrel cage type and is connected to one end of motor 32 for propelling cooling air through discharge ports 25 g.

FIG. 5 illustrates improved cooling airflow electric motor-driven pump 10 in accordance with the invention. Pump 10 is particularly adapted for transferring liquids, such as condensate generated by air conditioning and refrigeration systems from condensate collection pans or the like, to an integral reservoir of pump 10 comprising open top hollow body 12 and forming reservoir chamber 13, see FIG. 7. Reservoir body 12 is of generally rectangular configuration and is adapted to support generally planar, removable cover member 14, as illustrated. Fluid inlet ports 16, 17 and 18 are provided in cover member 14 for selective connection to a fluid inlet conduit, not shown. Fluid is discharged from pump 10 by way of discharge conduit 22, FIGS. 5 through 8, which is particularly adapted for forcible connection to a flexible fluid discharge hose, not shown. Reservoir cover 14 is releasably connected to reservoir body 12 by opposed depending elastically deflectable latch members, not shown. Reservoir body 12 is provided with spaced apart integral mounting brackets 12 b, FIGS. 5, 6 and 7.

As shown in FIGS. 5 and 6, pump 10 includes motor shroud or cover 24 which is of unique construction and advantageously encloses electric motor 32, FIG. 7, to be described further herein for driving pump impeller 40 of pump 10. Motor cover 24 further forms an enclosure for electronic controls 66 for operating pump motor 32 and an enclosure for open radial blade blower wheel 54 which is directly connected to pump motor rotor 36. Motor cover 24 is formed as a hollow shell-like member and includes blower wheel shroud 26 aerothermodynamically matched to blower wheel 54, air scoop 27 proximately located adjacent to blower wheel shroud 26 and disposed in a second part of motor cover 24, and means forming at least one cooling airflow flue 28 disposed in a third part of motor cover 24 and formed between air scoop 27 and fourth part 30 of motor cover 24.

Blower wheel shroud 26 comprises a generally cylindrical part and is provided with plurality of spaced apart tangential slots 31 extending generally vertically about the periphery of blower wheel shroud 26 forming cooling air discharge ports and adjacent to blower wheel 54 when motor cover 24 is disposed on reservoir cover 14 to provide for cooling air discharge from cooling air discharge chamber 26 a formed by air scoop 27. As shown in FIG. 6, tangential slots 31 are orientated to align with the air flow exit angle from blower wheel blades 54 b to enhance the aerodynamics of the cooling air flow through the cooling air discharge ports. Air scoop 27 is proximately located adjacent to blower wheel shroud 26 and disposed in a second part of motor cover 24. Air scoop 27 is a teardrop shaped configuration when view from the top and facilitates the air flow transition from cooling airflow flue 28 disposed in a third part of motor cover 24 to blower wheel 54. Cooling airflow flue 28 is disposed in a third part of motor cover 24. Cooling airflow flue 28 is shaped to act as a natural draft mechanism to facilitate the air flow from plurality of vertically extending spaced apart slots 25 forming cooling air inlet ports disposed in fourth part 30 of motor cover 24 across electric motor 32 windings and associated electronic controls 66 to air scoop 27. Fourth part 30 of motor cover 24 comprises a generally rectangular part and is provided with plurality of vertically extending spaced apart slots 25 forming cooling air inlet ports disposed in fourth part 30 and spaced from reservoir cover 14.

Blower wheel shroud 26 is integrally joined to air scoop 27 and fourth rectangular part 30 of motor cover 24. Blower wheel shroud 26 forms cover for at least of a portion of motor 32 and blower wheel 54. Cooling air flow flue 28 is also integrally joined to air scoop 27 and fourth rectangular part 30 of motor cover 24. Cooling air flow flue 28 forms a cover for at least control electronics 66. Parts 26, 27, 28 and 30 are preferably formed of a suitable molded plastic which is the case for reservoir cover 14 and reservoir body 12 also. As shown in FIGS. 5 and 6, motor cover 24 is preferably joined to reservoir cover 14 by spaced apart tabs 24 a, which are insertable in cooperating slots 14 b, FIG. 8, formed in reservoir cover 14. Accordingly, molded motor cover 24 may be easily snapped into and out of engagement with reservoir cover 14.

Referring to FIG. 7, pump 10 is provided with electric motor 32, suitably mounted within motor cover 24 and on reservoir cover 14. Motor 32 includes a rotor 34 suitably mounted in spaced apart bearings, not shown. Rotor 34 is operably connected to opposed coaxial rotatable motor output shaft parts 36 and 38. Shaft part 38 depends into reservoir 12 and is connected to centrifugal pump impeller 40. Impeller 40 is disposed in a chamber 42 formed by a pump housing part 44 which is suitably connected to the underside of reservoir cover 14 and includes reservoir sub-chamber 45 in communication with chamber 13 by way of vertical slot-like fluid inlet ports 46. Pump housing 44 is also provided with impeller inlet passage 47 and removable cover 48 to allow access to pump impeller 40. Pump discharge conduit or fitting 22 is threadedly connected to housing 44 at threaded bore 50. Suitable spring biased fluid discharge check valve 52 is interposed housing 44 and pump discharge conduit 22 to prevent back-flow from a pump discharge line, not shown, into chamber 42. As shown in FIGS. 5, 6 and 8, alternate fluid inlet ports 16 and 17 for a pump reservoir inlet line, not shown, are provided in cover member 14 and are formed with so-called knock-out plugs, as illustrated in FIGS. 5 and 6. Motor shaft part 36 supports and is drivingly connected to a open radial blade blower wheel 54, FIGS. 7 and 8, for rotation upon energization of motor 32. Accordingly, at any time that pump 10 is operating to discharge fluid from reservoir chamber 13, open radial blade blower wheel 54 is operating to drawing cooling air into an interior space 57, FIG. 7, of motor cover 24 through cooling air inlet ports 25 to provide a uniformly distributed flow of cooling air over motor 32 and electronic controls 66. Open radial blade blower wheel 54 is preferably made of impact resistant plastic, fabricated steel, stainless steel or cast aluminum, and includes impeller blades 54 b, FIG. 7. Cooling air propelled by blower wheel 54 is discharged at periphery 54 c of the blower wheel 54 and then through cooling air discharge ports 31. Thanks to the provision of air scoop 27, blower wheel 54 is operable to reside in space 26 a, FIG. 7, which provides, in essence, an airflow discharge chamber which is in communication with the cooling air discharge ports 31.

The construction and operation of pump 10 is believed to readily understandable to those of ordinary skill in the art based on the foregoing description. Conventional engineering plastics may be used to fabricate parts such as reservoir body 12, reservoir cover 14, motor cover 24, pump reservoir housing 44 and cover 48 and the discharge fitting 22. Impeller 40 and blower wheel 54 may also be formed of molded plastic although other engineering materials normally used for pump and fan construction may be utilized. Thanks to the shape of motor cover 24 and the location of inlet ports 25 and discharge ports 31 coupled to open radial blade blower wheel 54 the air flow is optimized across motor 32 and electronic controls 66 to dissipate heat in the most thermally efficient manner. Hence, improved motor cooling air flow is obtained relatively easily and in an uncomplicated arrangement.

Those skilled in the art will recognize the above-described features and advantages of the invention and that various substitutions and modifications may be made without departing from the scope and spirit of the appended claims.

REFERENCE CHARACTERS

-   10 Pump -   12 Reservoir Body -   12 a Integral Mounting Tab -   13 Reservoir Chamber -   14 Reservoir Cover -   14 b Slots -   16 Fluid Inlet Port -   17 Fluid Inlet Port -   18 Fluid Inlet Port -   22 Discharge Conduit -   24 Motor Cover -   24 a Tab -   25 Cooling Air Inlet Port -   26 Cylindrical Part -   26 a Air Scoop Chamber -   27 Air Scoop -   28 Air Flue -   30 Rectangular Part -   31 Cooling Air Discharge Port -   32 Electric Motor -   34 Motor Rotor -   36 Motor Shaft -   38 Motor Shaft -   40 Centrifugal Impeller -   42 Chamber -   44 Pump Housing -   45 Sub-chamber -   46 Slot -   47 Impeller Inlet Passage -   48 Cover -   50 Threaded Bore -   52 Check Valve -   54 Blower Wheel -   54 b Blade -   54 c Periphery -   66 Electronic Controls 

1. An improved cooling airflow electric motor-driven pump comprising: a reservoir body including a reservoir chamber for collecting liquid; a reservoir cover releasably connected to and disposed over the reservoir body and including a fluid inlet port for conducting liquid to the reservoir chamber; an open radial blade blower wheel for cooling air flow; an electric motor mounted on the reservoir cover including a first shaft part drivingly connected to a pump impeller and a second shaft part drivingly connected to the blower wheel; and a motor cover disposed over the motor and the blower wheel, the motor cover being releasably mounted on the reservoir cover, the motor cover including a blower wheel shroud aerothermodynamically matched to the blower wheel, an air scoop proximately located adjacent to the blower wheel shroud and disposed in a second part of the motor cover, and a means forming at least one cooling airflow flue disposed in a third part of the motor cover and formed between the air scoop second part and a fourth part of the motor cover.
 2. The improved cooling airflow pump of claim 1 wherein: the blower wheel shroud of the motor cover comprises a generally cylindrical part and is provided with a plurality of spaced apart tangential slots extending generally vertically about the blower wheel shroud periphery forming cooling air discharge ports and adjacent to the blower wheel when the motor cover is disposed on the reservoir cover to provide for cooling air discharge from a cooling air discharge chamber formed by the air scoop second part of the motor cover.
 3. The improved cooling airflow pump of claim 1 wherein: the fourth part of the motor cover comprises a generally rectangular part and is provided with a plurality of vertically extending spaced apart slots forming cooling air inlet ports disposed in the fourth part of the motor cover and spaced from the reservoir cover.
 4. The improved cooling airflow pump of claim 1 wherein: the blower wheel shroud of the motor cover is integrally joined to the air scoop second part of the motor cover and the fourth part of the motor cover and the blower wheel shroud of the motor cover forms a cover for at least of a portion of the motor.
 5. The improved cooling airflow pump of claim 1 wherein: the cooling air flow flue third part of the motor cover is integrally joined to the air scoop second part of the motor cover and the fourth part of the motor cover, and the cooling air flow flue third part of the motor cover forms a cover for at least the float control electronics for controlling operation of the motor.
 6. An improved cooling airflow electric motor-driven pump comprising: a reservoir body including a reservoir chamber for collecting liquid; a reservoir cover releasably connected to and disposed over the reservoir body; an open radial blade blower wheel for cooling air flow; an electric motor mounted on the reservoir cover including a first vertically extending shaft part drivingly connected to a pump impeller and a second vertically shaft part drivingly connected to the blower; and a motor cover disposed over the motor and the blower wheel, the motor cover being releasably mounted on the reservoir cover, the motor cover including a generally cylindrical first part of the motor cover forming a cooling air shroud and covering the blower wheel, a plurality of spaced apart tangential slots extending generally vertically formed in the first part of the motor cover adjacent to the blower wheel when the motor cover is disposed on the reservoir cover to provide for cooling air discharge from the cooling air shroud formed by the first part of the motor cover, an air scoop disposed in a second part of the motor cover, a means forming at least one cooling airflow flue disposed in a third part of the motor cover, a generally rectangular fourth part of the cover, and a plurality of vertically extending spaced apart slots forming cooling air inlet ports disposed in the fourth part of the motor cover and spaced from the reservoir cover.
 7. The improved cooling airflow pump of claim 6 wherein: the first part of the motor cover is integrally joined to the second and fourth parts of the motor cover, and the first part of the motor cover forms a cover for at least a portion of the motor.
 8. The improved cooling airflow pump of claim 6 wherein: the third part of the motor cover is integrally joined to the second and fourth parts of the motor cover, and the third part of the motor cover forms a cover for at least the float control electronics for controlling operation of the motor.
 9. An improved cooling airflow electric motor-driven pump comprising: a reservoir body including a reservoir chamber for collecting liquid; a reservoir cover releasably connected to and disposed over the reservoir body; a fluid inlet port for conducting liquid to the reservoir chamber, an open radial blade blower wheel for cooling air flow; an electric motor mounted on the reservoir cover including a first shaft part drivingly connected to a pump impeller and a second shaft part drivingly connected to the blower wheel; and a motor cover disposed over the motor and the blower wheel, the motor cover being releasably mounted on the reservoir cover, the motor cover including a plurality of spaced apart tangential slots extending generally vertically forming cooling air discharge ports and disposed in a first generally cylindrical part of the motor cover, and a plurality of vertically extending spaced apart slots forming cooling air inlet ports disposed in a second part of the motor cover and spaced from the reservoir cover.
 10. The improved cooling airflow pump of claim 9 wherein: the first part of the motor cover is integrally joined to the second part, and the first part of the motor cover forms a cooling air discharge shroud containing at least part of the motor and the blower wheel.
 11. The improved cooling airflow pump of claim 9 wherein: the second part of the motor cover is integrally joined to the first, and the second part of the motor cover forms a cover for at least the float control electronics for controlling operation of the motor.
 12. An improved cooling airflow device for an electric motor-driven condensate pump, the device comprising: a cover having a generally cylindrical first part, a generally teardrop-shaped second part, a generally trapezoidal third part and a generally rectangular fourth part; a plurality of spaced apart tangential slots extending generally vertically disposed in the first part of the cover and forming cooling air discharge ports; a plurality of vertically extending spaced apart slots disposed in the fourth part of the motor cover and forming cooling air inlet ports; and an open radial blade blower wheel aerothermodynamically coupled to the cooling air inlet and discharge ports to optimize airflow across the electric motor to dissipate heat.
 13. The improved cooling airflow device of claim 12 wherein: the first part of the motor cover is integrally joined to the second and fourth parts of the motor cover, and the first part of the motor cover forms a cooling air discharge shroud containing at least part of the motor and the blower wheel.
 14. The improved cooling airflow device of claim 12 wherein: the third part of the motor cover is integrally joined to the second and fourth parts of the motor cover, and the third part of the motor cover forms a cover for at least the float control electronics for controlling operation of the motor. 